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1.
Transl Vis Sci Technol ; 9(7): 37, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32832242

RESUMEN

Purpose: To examine repeatability and reproducibility of foveal cone density measurements in patients with CNGA3 - and CNGB3-associated achromatopsia (ACHM) using split-detection adaptive optics scanning light ophthalmoscopy (AOSLO). Methods: Thirty foveae from molecularly confirmed subjects with ACHM, half of whom harbored disease-causing variants in CNGA3 and half in CNGB3, underwent nonconfocal split-detection AOSLO imaging. Cone photoreceptors within the manually delineated rod-free zone were manually identified twice by two independent observers. The coordinates of the marked cones were used for quantifying foveal cone density. Cone density and difference maps were generated to compare cone topography between trials. Results: We observed excellent intraobserver repeatability in foveal cone density estimates, with intraclass correlation coefficients (ICCs) ranging from 0.963 to 0.991 for CNGA3 and CNGB3 subjects. Interobserver reproducibility was also excellent for both CNGA3 (ICC = 0.952; 95% confidence interval [CI], 0.903-1.0) and CNGB3 (ICC = 0.968; 95% CI, 0.935-1.0). However, Bland-Altman analysis revealed bias between observers. Conclusions: Foveal cone density can be measured using the described method with good repeatability and reproducibility both for CNGA3- and CNGB3-associated ACHM. Any degree of bias observed among the observers is of uncertain clinical significance but should be evaluated on a study-specific basis. Translational Relevance: This approach could be used to explore disease natural history, as well as to facilitate stratification of patients and monitor efficacy of interventions for ongoing and upcoming ACHM gene therapy trials.

2.
Prog Retin Eye Res ; : 100875, 2020 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-32659431

RESUMEN

Glaucoma and other optic neuropathies are characterized by progressive dysfunction and loss of retinal ganglion cells and their axons. Given the high prevalence of glaucoma-related blindness and the availability of treatment options, improving the diagnosis and precise monitoring of progression in these conditions is paramount. Here we review recent progress in the development of novel biomarkers for glaucoma in the context of disease pathophysiology and we propose future steps for the field, including integration of exploratory biomarker outcomes into prospective therapeutic trials. We anticipate that, when validated, some of the novel glaucoma biomarkers discussed here will prove useful for clinical diagnosis and prediction of progression, as well as monitoring of clinical responses to standard and investigational therapies.

3.
Opt Express ; 28(13): 18876-18886, 2020 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-32672177

RESUMEN

Wavefront estimation from slope sensor data is often achieved by fitting measured slopes with Zernike polynomial derivatives averaged over the sampling subapertures. Here we discuss how the calculation of these average derivatives can be reduced to one-dimensional integrals of the Zernike polynomials, rather than their derivatives, along the perimeter of each subaperture. We then use this result to derive closed-form expressions for the average Zernike polynomial derivatives over polygonal areas, only requiring evaluation of polynomials at the polygon vertices. Finally, these expressions are applied to simulated Shack-Hartmann wavefront sensors with 7 and 23 fully illuminated lenslets across a circular pupil, with their accuracy and calculation time compared against commonly used integration methods.

5.
Invest Ophthalmol Vis Sci ; 61(3): 40, 2020 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-32203983

RESUMEN

Purpose: The purpose of this study was to report GNAT2-associated achromatopsia (GNAT2-ACHM) natural history, characterize photoreceptor mosaic, and determine a therapeutic window for potential intervention. Methods: Patients with GNAT2-ACHM were recruited from a single tertiary referral eye center (Moorfields Eye Hospital, London, UK). We performed longitudinal clinical evaluation and ophthalmic examination, and multimodal retinal imaging, including adaptive optics scanning light ophthalmoscopy, quantitative analysis of the cone mosaic, and outer nuclear layer (ONL) thickness, including cone densities evaluation in selected regions of interest and comparison with reported healthy controls. Results: All nine subjects (3 women) presented with nystagmus, decreased visual acuity (VA), light sensitivity, and highly variable color vision loss. One patient had normal color vision and better VA. Mean VA was 1.01 (±0.10) logarithms of the minimal angle of resolution (LogMAR) at baseline, and 1.04 (±0.10) LogMAR after a mean follow-up (range) of 7.6 years (1.7-12.8 years). Optical coherence tomography showed preservation of the foveal ellipsoid zone (EZ; n = 8; 88.9%), and EZ disruption (n = 1; 11.1%). Mean ONL thickness (range, ± SD) was 84.72 µm (28.57-113.33, ± 25.46 µm) and 86.47 µm (28.57-113.33, ± 24.65 µm) for right and left eyes, respectively. Mean cone densities (±SD) at 190 µm, 350 µm, and 500 µm from the foveal center, were 48.4 (±24.6), 37.8 (±14.7), and 30.7 (±9.9), ×103 cones/mm2, respectively. Mean cone densities were lower than these of unaffected individuals, but with an overlap. Conclusions: The cone mosaic in GNAT2-ACHM is relatively well preserved, potentially allowing for a wide therapeutic window for cone-directed interventions.


Asunto(s)
Defectos de la Visión Cromática/genética , Defectos de la Visión Cromática/patología , Subunidades gamma de la Proteína de Unión al GTP/genética , Células Fotorreceptoras Retinianas Conos/patología , Adolescente , Adulto , Niño , Pruebas de Percepción de Colores , Electrorretinografía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Imagen Multimodal , Nistagmo Patológico/diagnóstico , Oftalmoscopía , Imagen Óptica , Linaje , Fenotipo , Tomografía de Coherencia Óptica , Agudeza Visual/fisiología , Adulto Joven
6.
Neurophotonics ; 6(4): 041101, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31824978

RESUMEN

The guest editorial provides an introduction to the Special Section on Advanced Retinal Imaging: Instrumentation, Methods, and Applications.

7.
Invest Ophthalmol Vis Sci ; 60(15): 5112-5123, 2019 12 02.
Artículo en Inglés | MEDLINE | ID: mdl-31826238

RESUMEN

Purpose: To perform deep phenotyping of subjects with PDE6C achromatopsia and examine disease natural history. Methods: Eight subjects with disease-causing variants in PDE6C were assessed in detail, including clinical phenotype, best-corrected visual acuity, fundus autofluorescence, and optical coherence tomography. Six subjects also had confocal and nonconfocal adaptive optics scanning light ophthalmoscopy, axial length, international standard pattern and full-field electroretinography (ERG), short-wavelength flash (S-cone) ERGs, and color vision testing. Results: All subjects presented with early-onset nystagmus, decreased best-corrected visual acuity, light sensitivity, and severe color vision loss, and five of them had high myopia. We identified three novel disease-causing variants and provide phenotype data associated with nine variants for the first time. No subjects had foveal hypoplasia or residual ellipsoid zone (EZ) at the foveal center; one had an absent EZ, three had a hyporeflective zone, and four had outer retinal atrophy. The mean width of the central EZ lesion on optical coherence tomography at baseline was 1923 µm. The mean annual increase in EZ lesion size was 48.3 µm. Fundus autofluorescence revealed a central hypoautofluorescence with a surrounding ring of increased signal (n = 5). The mean hypoautofluorescent area at baseline was 3.33 mm2 and increased in size by a mean of 0.13 mm2/year. Nonconfocal adaptive optics scanning light ophthalmoscopy revealed residual foveal cones in only one of two cases. Full-field ERGs were consistent with severe generalized cone system dysfunction but with relative preservation of S-cone sensitivity. Conclusions: PDE6C retinopathy is a severe cone dysfunction syndrome often presenting as typical achromatopsia but without foveal hypoplasia. Myopia and slowly progressive maculopathy are common features. There are few (if any) residual foveal cones for intervention in older adults.


Asunto(s)
Defectos de la Visión Cromática/genética , Visión de Colores/fisiología , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 6/genética , Proteínas del Ojo/genética , Agudeza Visual , Adolescente , Adulto , Niño , Defectos de la Visión Cromática/diagnóstico , Defectos de la Visión Cromática/metabolismo , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 6/metabolismo , Electrorretinografía , Proteínas del Ojo/metabolismo , Femenino , Estudios de Seguimiento , Predicción , Humanos , Masculino , Persona de Mediana Edad , Oftalmoscopía , Fenotipo , Tomografía de Coherencia Óptica/métodos , Adulto Joven
8.
Opt Lett ; 44(17): 4151-4154, 2019 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-31465350

RESUMEN

The Shack-Hartmann wavefront sensor samples a beam of light using an array of lenslets, each of which creates an image onto a pixelated sensor. These images translate from their nominal position by a distance proportional to the average wavefront slope over the corresponding lenslet. This principle fails in partially and/or non-uniformly illuminated lenslets when the lenslet array is focused to maximize peak intensity, leading to image centroid bias. Here, we show that this bias is due to the low Fresnel number of the lenslets, which shifts the diffraction focus away from the geometrical focus. We then demonstrate how the geometrical focus can be empirically found by minimizing the bias in partially illuminated lenslets.

9.
Opt Lett ; 44(17): 4167-4170, 2019 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-31465354

RESUMEN

Images formed by individual Shack-Hartmann wavefront sensor lenslets are displaced proportionally to the average wavefront slope over their aperture. This principle fails when the lenslet illumination is non-uniform. Here we demonstrate that the resulting error is proportional to the linear component of the illumination intensity, the quadratic wavefront component, and the lenslet size. For illustrative purposes, we compare the error due to centered Gaussian illumination decaying by 30% at the pupil edge against the error due to assuming the wavefront at the lenslet center being equal to the wavefront average across each lenslet. When testing up to ninth-order Zernike polynomial wavefronts and simulating nine lenslets across the pupil, the maximum centroid errors due to non-uniform illumination and sampling are 1.4% and 21%, respectively, and 0.5% and 6.7% when considering 25 lenslets across the pupil in the absence of other sources of error.

10.
Biomed Opt Express ; 10(8): 3815-3832, 2019 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-31452977

RESUMEN

Quantification of the human rod and cone photoreceptor mosaic in adaptive optics scanning light ophthalmoscope (AOSLO) images is useful for the study of various retinal pathologies. Subjective and time-consuming manual grading has remained the gold standard for evaluating these images, with no well validated automatic methods for detecting individual rods having been developed. We present a novel deep learning based automatic method, called the rod and cone CNN (RAC-CNN), for detecting and classifying rods and cones in multimodal AOSLO images. We test our method on images from healthy subjects as well as subjects with achromatopsia over a range of retinal eccentricities. We show that our method is on par with human grading for detecting rods and cones.

11.
Opt Express ; 27(8): 11205-11226, 2019 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-31052968

RESUMEN

Nodal aberration theory is used to calculate the third-order aberrations that result in image blur for an unobscured modified 4f relay (2f1 + 2f2) formed by two tilted spherical mirrors for objects at infinity (infinite conjugate) and near the front focal plane of the first mirror (finite conjugate). The field-averaged wavefront variance containing only non-rotationally symmetric aberration coefficients is then proposed as an optimization metric. Analytical and ray tracing optimization are demonstrated through sample designs. The particular cases of in-plane and orthogonal folding of the optical axis ray are discussed, followed by an analysis of a modified 2f1 + 2f2 relay in which the distance of the first mirror to the object or pupil is allowed to vary for aberration correction. The sensitivity of the infinite conjugate 2f1 + 2f2 relay to the input marginal ray angle is also examined. Finally, the optimization of multiple conjugate systems through a weighted combination of wavefront variances is proposed.

12.
Vision Res ; 158: 90-99, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30826354

RESUMEN

Cone photoreceptors of the 13-lined ground squirrel (13-LGS) undergo reversible structural changes during hibernation, including cone outer segment disc degeneration and inner segment mitochondria depletion. Here, we evaluated cone structure with adaptive optics scanning light ophthalmoscopy (AOSLO) before, during, and after hibernation. Also, intra-animal comparisons of cone structure were made at distinct physiological states (pre-hibernation, torpor, interbout euthermia, and post-hibernation) with AOSLO and transmission electron microscopy. Our results indicate that the 13-LGS cone mosaic is only transiently affected by structural remodeling during hibernation. Outer segment remodeling starts during torpid states during a period of fall transition in room temperature, with more severe structural changes during bouts of torpor in cold temperature. Cones return to euthermic-like structure during brief periods of interbout euthermia and recover normal waveguiding properties as soon as 24 h post-hibernation. Cone structure is visible with split-detector AOSLO throughout hibernation, providing evidence that intact outer segments are not necessary to visualize cones with this technique. Despite the changes to cone structure during hibernation, cone density and packing remained unchanged throughout the seasonal cycle. Pairing non-invasive imaging with ultrastructural assessment may provide insight to the biological origins of cone photoreceptor signals observed with AOSLO.


Asunto(s)
Células Fotorreceptoras Retinianas Conos/citología , Sciuridae/anatomía & histología , Estaciones del Año , Animales , Femenino , Hibernación , Masculino , Microscopía Electrónica de Transmisión , Oftalmoscopía/métodos , Fotoperiodo , Células Fotorreceptoras Retinianas Conos/ultraestructura
13.
Invest Ophthalmol Vis Sci ; 60(1): 383-396, 2019 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-30682209

RESUMEN

Purpose: To investigate retinal structure in subjects with CNGA3-associated achromatopsia and evaluate disease symmetry and intrafamilial variability. Methods: Thirty-eight molecularly confirmed subjects underwent ocular examination, optical coherence tomography (OCT), and nonconfocal split-detection adaptive optics scanning light ophthalmoscopy (AOSLO). OCT scans were used for evaluating foveal hypoplasia, grading foveal ellipsoid zone (EZ) disruption, and measuring outer nuclear layer (ONL) thickness. AOSLO images were used to quantify peak foveal cone density, intercell distance (ICD), and the coefficient of variation (CV) of ICD. Results: Mean (±SD) age was 25.9 (±13.1) years. Mean (± SD) best corrected visual acuity (BCVA) was 0.87 (±0.14) logarithm of the minimum angle of resolution. Examination with OCT showed variable disruption or loss of the EZ. Seven subjects were evaluated for disease symmetry, with peak foveal cone density, ICD, CV, ONL thickness, and BCVA not differing significantly between eyes. A cross-sectional evaluation of AOSLO imaging showed a mean (±SD) peak foveal cone density of 19,844 (±13,046) cones/mm2. There was a weak negative association between age and peak foveal cone density (r = -0.397, P = 0.102), as well as between EZ grade and age (P = 0.086). Conclusions: The remnant cone mosaics were irregular and variably disrupted, with significantly lower peak foveal cone density than unaffected individuals. Variability was also seen among subjects with identical mutations. Therefore, subjects should be considered on an individual basis for stratification in clinical trials. Interocular symmetry suggests that both eyes have comparable therapeutic potential and the fellow eye can serve as a valid control. Longitudinal studies are needed, to further examine the weak negative association between age and foveal cone structure observed here.


Asunto(s)
Defectos de la Visión Cromática/diagnóstico por imagen , Defectos de la Visión Cromática/genética , Canales Catiónicos Regulados por Nucleótidos Cíclicos/genética , Retina/diagnóstico por imagen , Adolescente , Adulto , Niño , Estudios Transversales , Electrorretinografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oftalmoscopía , Óptica y Fotónica , Células Fotorreceptoras de Vertebrados/patología , Tomografía de Coherencia Óptica , Agudeza Visual/fisiología , Adulto Joven
14.
Retina ; 39(3): 570-580, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29190250

RESUMEN

PURPOSE: To examine the features of the tapetal-like reflex (TLR) in female carriers of RPGR-associated retinopathy by means of adaptive optics scanning light ophthalmoscopy (AOSLO) and spectral domain optical coherence tomography. METHODS: Nine molecularly confirmed RPGR carriers and three healthy controls underwent ocular examination and the following retinal imaging modalities: color photography, near-infrared reflectance, fundus autofluorescence, spectral domain optical coherence tomography, and AOSLO. After identifying TLR areas across all imaging modalities, normalized local contrast of outer retinal bands on spectral domain optical coherence tomography was calculated and AOSLO-acquired photoreceptor mosaic analysis was performed. RESULTS: Seven carriers had TLR areas, which colocalized with increased rod photoreceptor reflectivity on confocal AOSLO and reduced cone photoreceptor densities. Parafoveal TLR areas also exhibited reduced local contrast (i.e., increased reflectivity) of the outer retinal bands on spectral domain optical coherence tomography (inner segment ellipsoid zone and outer segment interdigitation zone). Healthy controls did not show TLR. CONCLUSION: The cellular resolution provided by AOSLO affords the characterization of the photoreceptor mosaic in RPGR carriers with a TLR. Features revealed include reduced cone density, increased cone inner segment diameter, and increased rod outer segment reflectivity.


Asunto(s)
Proteínas del Ojo/genética , Retina/patología , Retinitis Pigmentosa , Adulto , Femenino , Tamización de Portadores Genéticos , Heterocigoto , Humanos , Masculino , Persona de Mediana Edad , Oftalmoscopía/métodos , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras Retinianas Bastones/patología , Retinitis Pigmentosa/genética , Retinitis Pigmentosa/patología , Agudeza Visual
15.
Invest Ophthalmol Vis Sci ; 59(11): 4639-4652, 2018 09 04.
Artículo en Inglés | MEDLINE | ID: mdl-30372733

RESUMEN

Purpose: Cone photoreceptor cells can be noninvasively imaged in the living human eye by using nonconfocal adaptive optics scanning ophthalmoscopy split detection. Existing metrics, such as cone density and spacing, are based on simplifying cone photoreceptors to single points. The purposes of this study were to introduce a computer-aided approach for segmentation of cone photoreceptors, to apply this technique to create a normal database of cone diameters, and to demonstrate its use in the context of existing metrics. Methods: Cone photoreceptor segmentation is achieved through a circularly constrained active contour model (CCACM). Circular templates and image gradients attract active contours toward cone photoreceptor boundaries. Automated segmentation from in vivo human subject data was compared to ground truth established by manual segmentation. Cone diameters computed from curated data (automated segmentation followed by manual removal of errors) were compared with histology and published data. Results: Overall, there was good agreement between automated and manual segmentations and between diameter measurements (n = 5191 cones) and published histologic data across retinal eccentricities ranging from 1.35 to 6.35 mm (temporal). Interestingly, cone diameter was correlated to both cone density and cone spacing (negatively and positively, respectively; P < 0.01 for both). Application of the proposed automated segmentation to images from a patient with late-onset retinal degeneration revealed the presence of enlarged cones above individual reticular pseudodrusen (average 23.0% increase, P < 0.05). Conclusions: CCACM can accurately segment cone photoreceptors on split detection images across a range of eccentricities. Metrics derived from this automated segmentation of adaptive optics retinal images can provide new insights into retinal diseases.


Asunto(s)
Oftalmoscopía/métodos , Óptica y Fotónica , Células Fotorreceptoras Retinianas Conos/patología , Degeneración Retiniana/diagnóstico , Adulto , Algoritmos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Células Fotorreceptoras Retinianas Conos/citología , Tomografía de Coherencia Óptica , Adulto Joven
16.
Biomed Opt Express ; 9(8): 3740-3756, 2018 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-30338152

RESUMEN

Fast and reliable quantification of cone photoreceptors is a bottleneck in the clinical utilization of adaptive optics scanning light ophthalmoscope (AOSLO) systems for the study, diagnosis, and prognosis of retinal diseases. To-date, manual grading has been the sole reliable source of AOSLO quantification, as no automatic method has been reliably utilized for cone detection in real-world low-quality images of diseased retina. We present a novel deep learning based approach that combines information from both the confocal and non-confocal split detector AOSLO modalities to detect cones in subjects with achromatopsia. Our dual-mode deep learning based approach outperforms the state-of-the-art automated techniques and is on a par with human grading.

17.
J Vis ; 18(8): 6, 2018 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-30105385

RESUMEN

Psychophysical inferences about the neural mechanisms supporting spatial vision can be undermined by uncertainties introduced by optical aberrations and fixational eye movements, particularly in fovea where the neuronal grain of the visual system is fine. We examined the effect of these preneural factors on photopic spatial summation in the human fovea using a custom adaptive optics scanning light ophthalmoscope that provided control over optical aberrations and retinal stimulus motion. Consistent with previous results, Ricco's area of complete summation encompassed multiple photoreceptors when measured with ordinary amounts of ocular aberrations and retinal stimulus motion. When both factors were minimized experimentally, summation areas were essentially unchanged, suggesting that foveal spatial summation is limited by postreceptoral neural pooling. We compared our behavioral data to predictions generated with a physiologically-inspired front-end model of the visual system, and were able to capture the shape of the summation curves obtained with and without pre-retinal factors using a single postreceptoral summing filter of fixed spatial extent. Given our data and modeling, neurons in the magnocellular visual pathway, such as parasol ganglion cells, provide a candidate neural correlate of Ricco's area in the central fovea.


Asunto(s)
Movimientos Oculares/fisiología , Fijación Ocular/fisiología , Fóvea Central/fisiología , Procesamiento Espacial/fisiología , Vías Visuales/fisiología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Psicofísica/métodos , Umbral Sensorial/fisiología
18.
Transl Vis Sci Technol ; 7(3): 21, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29946495

RESUMEN

Purpose: Recent advances in adaptive optics scanning light ophthalmoscopy (AOSLO) have enabled visualization of cone inner segments through nonconfocal split-detection, in addition to rod and cone outer segments revealed by confocal reflectance. Here, we examined the interobserver reliability of cone density measurements in both AOSLO imaging modalities. Methods: Five normal subjects (nine eyes) were imaged along the horizontal and vertical meridians using a custom AOSLO with confocal and nonconfocal split-detection modalities. The resulting images were montaged using a previously described semiautomatic algorithm. Regions of interest (ROIs) were selected from the confocal montage at 190 µm, and from split-detection and confocal montages at 900 and 1800 µm from the fovea. Four observers (three experts, one naïve) manually identified cone locations in each ROI, and these locations were used to calculate bound densities. Intraclass correlation coefficients and Dice's coefficients were calculated to assess interobserver agreement. Results: Interobserver agreement was high in cone-only images (confocal 190 µm: 0.85; split-detection 900 µm: 0.91; split-detection 1800 µm: 0.89), moderate in confocal images at 900 µm (0.68), and poor in confocal images at 1800 µm (0.24). Excluding the naïve observer data substantially increased agreement within confocal images (190 µm: 0.99; 900 µm: 0.80; 1800 µm: 0.68). Conclusions: Interobserver measurements of cone density are more reliable in rod-free retinal images. Moreover, when using manual cell identification, it is essential that observers are trained, particularly for confocal AOSLO images. Translational Relevance: This study underscores the need for additional reliability studies in eyes containing pathology where identifying cones can be substantially more difficult.

19.
Sci Rep ; 8(1): 7911, 2018 05 21.
Artículo en Inglés | MEDLINE | ID: mdl-29784939

RESUMEN

We present a robust deep learning framework for the automatic localisation of cone photoreceptor cells in Adaptive Optics Scanning Light Ophthalmoscope (AOSLO) split-detection images. Monitoring cone photoreceptors with AOSLO imaging grants an excellent view into retinal structure and health, provides new perspectives into well known pathologies, and allows clinicians to monitor the effectiveness of experimental treatments. The MultiDimensional Recurrent Neural Network (MDRNN) approach developed in this paper is the first method capable of reliably and automatically identifying cones in both healthy retinas and retinas afflicted with Stargardt disease. Therefore, it represents a leap forward in the computational image processing of AOSLO images, and can provide clinical support in on-going longitudinal studies of disease progression and therapy. We validate our method using images from healthy subjects and subjects with the inherited retinal pathology Stargardt disease, which significantly alters image quality and cone density. We conduct a thorough comparison of our method with current state-of-the-art methods, and demonstrate that the proposed approach is both more accurate and appreciably faster in localizing cones. As further validation to the method's robustness, we demonstrate it can be successfully applied to images of retinas with pathologies not present in the training data: achromatopsia, and retinitis pigmentosa.


Asunto(s)
Algoritmos , Aprendizaje Profundo , Degeneración Macular/congénito , Retina/metabolismo , Células Fotorreceptoras Retinianas Conos/metabolismo , Estudios de Casos y Controles , Humanos , Degeneración Macular/metabolismo , Degeneración Macular/patología , Redes Neurales de la Computación , Retina/citología , Células Fotorreceptoras Retinianas Conos/citología , Enfermedad de Stargardt , Agudeza Visual
20.
Biomed Opt Express ; 9(4): 1477-1491, 2018 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-29675296

RESUMEN

Chromatic aberrations are an important design consideration in high resolution, high bandwidth, refractive imaging systems that use visible light. Here, we present a fiber-based spectral/Fourier domain, visible light OCT ophthalmoscope corrected for the average longitudinal chromatic aberration (LCA) of the human eye. Analysis of complex speckles from in vivo retinal images showed that achromatization resulted in a speckle autocorrelation function that was ~20% narrower in the axial direction, but unchanged in the transverse direction. In images from the improved, achromatized system, the separation between Bruch's membrane (BM), the retinal pigment epithelium (RPE), and the outer segment tips clearly emerged across the entire 6.5 mm field-of-view, enabling segmentation and morphometry of BM and the RPE in a human subject. Finally, cross-sectional images depicted distinct inner retinal layers with high resolution. Thus, with chromatic aberration compensation, visible light OCT can achieve volume resolutions and retinal image quality that matches or exceeds ultrahigh resolution near-infrared OCT systems with no monochromatic aberration compensation.

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